Associations between physical fitness and academic achievement among Chinese school-aged children: the role of sociodemographic moderators

The current state of evidence concerning the associations between physical fitness (PF) and academic achievement (AA) among children is mixed, suggesting that specific moderators may influence those relationships. Thus, this study aimed to examine (i) the associations between PF and AA among Chinese school-aged children and (ii) whether sex, grade, and parental education moderated those associations. Methods: In this cross-sectional study, we examined PF and AA in 7142 children from the Beijing area (mean age = 8.24 ± 1.33 years; 54.3% boys). PF was assessed using the Chinese National Student Physical Fitness Standard (CNSPFS) battery, demographic information was collected via standardized questionnaires, and AA in reading, mathematics, and English was evaluated using standardized school tests. Because timed sit-ups were administered only in Grades 3–6 and the 50 m × 8 shuttle run only in Grades 5–6, the hierarchical regressions were interpreted as staged models matched to test availability, and moderation results were further probed using conditional-effects analyses. Results: In the fully adjusted models, lower BMI was associated with better reading scores ( β = −0.060, p = 0.005); higher rope-skipping performance was associated with better reading (β = 0.095, p < 0.001), mathematics ( β = 0.113, p < 0.001), and English scores ( β = 0.106, p < 0.001); better sit-up performance was associated with better reading (β = 0.052, p = 0.015), mathematics ( β = 0.230, p < 0.001), and English scores ( β = 0.122, p < 0.001); higher vital capacity was associated with mathematics ( β = 0.360–0.373 across adjusted models, p < 0.001) and English ( β = 0.109–0.111, p < 0.001); and shorter 50 m sprint and 50 m × 8 shuttle-run times were associated with better mathematics performance ( β = −0.246 and −0.206, respectively; both p < 0.001). Sex, grade, and parental education moderated several of these associations, with the clearest patterns observed for VC and sprint performance. Conclusion: This study provides evidence for positive associations between selected PF indicators and AA in Chinese school-aged children and shows that these associations vary according to sex, grade, and parental education. Future longitudinal and experimental studies are needed to clarify directionality and mechanisms.